Grab a Special Pikachu that knows the move Sing in Pokémon Sword or Pokémon Shield! To unlock your Special Pikachu you just need to enter the following code in the Mystery Gift menu: P25MUS1C
Instructions:
1. Launch your Pokémon Sword or Pokémon Shield game and select Mystery Gift.
2. Select "Get a Mystery Gift", "Get with Code" and enter your code.